U.S. patent application number 09/928892 was filed with the patent office on 2002-06-20 for headlight for vehicle for producing a low beam and at least one light beam with greater range.
Invention is credited to Boebel, Doris, Hamm, Michael, Rosenhahn, Ernst-Olaf, Thieringer, Walter, Wuestenhagen, Rainer.
Application Number | 20020075693 09/928892 |
Document ID | / |
Family ID | 7652980 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020075693 |
Kind Code |
A1 |
Rosenhahn, Ernst-Olaf ; et
al. |
June 20, 2002 |
Headlight for vehicle for producing a low beam and at least one
light beam with greater range
Abstract
A headlight for a vehicle for producing a low beam and at least
one light beam with a greater distance, the headlight comprising a
light source, a reflector, the light source and the reflector
together forming a headlight unit, an electrically adjusting device
for changing a relative position between the light source and the
reflector, a light width adjusting device for turning the headlight
insert about an at least approximately horizontally extending axis,
and a safety device operative for monitoring at least indirectly an
operation of the adjusting device and in the case of an error when
the adjusting device operates not in an orderly manner, the safety
device reduces an electric power with which the light source is
operated and/or reduces a distance of a light beam produced by the
headlight unit.
Inventors: |
Rosenhahn, Ernst-Olaf;
(Bodelshausen, DE) ; Hamm, Michael; (Pfullingen,
DE) ; Thieringer, Walter; (Reutlingen, DE) ;
Wuestenhagen, Rainer; (Holzgerlingen, DE) ; Boebel,
Doris; (Stuttgart, DE) |
Correspondence
Address: |
STRIKER, STRIKER & STENBY
103 East Neck Road
Huntington
NY
11743
US
|
Family ID: |
7652980 |
Appl. No.: |
09/928892 |
Filed: |
August 13, 2001 |
Current U.S.
Class: |
362/513 ;
362/263; 362/276; 362/277; 362/286; 362/512; 362/514; 362/523 |
Current CPC
Class: |
F21S 41/657 20180101;
B60Q 1/1415 20130101; B60Q 11/00 20130101 |
Class at
Publication: |
362/513 ;
362/512; 362/514; 362/523; 362/276; 362/277; 362/286; 362/263 |
International
Class: |
F21V 017/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 18, 2000 |
DE |
100 40 573.8 |
Claims
What is claimed as new and desired to be protected by Letters
Patent is set forth in the appended claims.
1. A headlight for a vehicle for producing a low beam and at least
one light beam with a greater distance, the headlight comprising a
light source; a reflector, said light source and said reflector
together forming a headlight unit; an electrically adjusting device
for changing a relative position between said light source and said
reflector; a light width adjusting device for turning said
headlight insert about an at least approximately horizontally
extending axis; and a safety device operative for monitoring at
least indirectly an operation of said adjusting device and in the
case of an error when said adjusting device operates not in an
orderly manner, said safety device reduces an electric power with
which said light source is operated and/or reduces a distance of a
light beam produced by said headlight unit.
2. A headlight as defined in claim 1, wherein said safety device is
operative for monitoring an operational current of said adjusting
device as to whether it deviates from a predetermined operational
current.
3. A headlight as defined in claim 1, wherein said safety device
(is operative for) moniting a relative position between said light
source and said reflector as to whether it corresponds to a
predetermined relative position.
4. A headlight as defined in claim 1, wherein said safety device is
formed so that in the case of an error said light source is put out
of operation.
5. A headlight as defined in claim 1, wherein in the case of error
said light width adjusting device is controlled by said safety
device, so that said headlight unit is turned downwardly and
thereby a distance of light beam produced by said headlight unit is
reduced.
6. A headlight as defined in claim 1, wherein said adjusting device
includes an electric drive motor which is formed as a stepper
motor.
7. A headlight as defined in claim 1, wherein said light source is
a gas discharge lamp which is provided for its operation with an
electrical preswitching device, said safety device in the case of
error controls said preswitching device for reducing an electric
power with which said gas discharge lamp is operated by said
preswitching device.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to headlight for vehicle for
producing a low beam and at least one light beam with a greater
range.
[0002] A headlight of this type is disclosed for example in the
patent document DE 44 35 507 A1. This headlight has a light source
and a reflector, which forms a headlight insert. The headlight has
an electrical adjusting device for adjusting the relative position
between the light source and the reflector in order to provide the
low beam and the light beam with a greater distance. The headlight
also has a light width adjusting device, which is operative for
turning the headlight insert for adjusting the light width of the
light bundle emitted by the headlight about an at least
approximately horizontally extending axis. In the case of a faulty
function of the adjusting device, the relative position between the
light source and the reflector remains within the position which is
predetermined for producing the light beam with the greater
distance, whereby in countertraffic a blinding is caused, which
must be avoided.
SUMMARY OF THE INVENTION
[0003] Accordingly, it si an object of the present invention to
provide a headlight of the above mentioned general type which
avoids the disadvantages of the prior art.
[0004] In keeping with these objects and with others which will
become apparent hereinafter, one feature of present invention
resides, briefly stated in a headlight which has a safety device
for monitoring at least indirectly the operation of the adjusting
device, and in the event of a failure when the adjusting device
does not operate in an orderly function, the electrical power with
which the light source is operated is reduced and/or the distance
of the light beam produced by the headlight insert is reduced.
[0005] When the headlight is designed in accordance with the
present invention, the safety device recognizing a faulty
functioning of the adjusting device, and a blinding of the
countertraffic can be avoided. This can be performed by reducing
the power with which the light source is operated and/or by turning
the headlight insert downwardly by the light width adjusting device
for reducing the light width.
[0006] The novel features which are considered as characteristic
for the present invention are set forth in particular in the
appended claims. The invention itself, however, both as to its
construction and its method of operation, together with additional
objects and advantages thereof, will be best understood from the
following description of specific embodiments when read in
connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a view showing a headlight in accordance with the
present invention in a vertical longitudinal section;
[0008] FIG. 2 is a view showing a measuring screen which is
arranged in front of the headlight in accordance with the present
invention and illuminated by a low beam produced with the
headlight; and
[0009] FIG. 3 is a view showing a measuring screen during
illumination by a light beam produced with the reflector and having
a greater distance.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] FIG. 1 shows a headlight for a vehicle, in particular for a
motor vehicle, for alternating generation of a low beam and at
least one light beam with a greater distance for example a high
beam. The headlight has the reflector 10 and a light source 12
which is an incandescent lamp or preferably a gas discharge lamp.
The reflector 10 with the light source 12 form a headlight insert
14 which is adjustably arranged in a holder or a housing 16. The
light outlet opening of the housing 16 is covered with a light
permeable member or disk 18 composed of glass or plastic. It can be
formed as a smooth disk or at least a partially provided with
optical profiles for a deviation and/or dispersion of the light.
The reflector 10 is a concavely curved and its apex region has an
opening 19 for the light source 12.
[0011] The relative position between the light source 12 and the
reflector 10 is changeable, in particular by moving the light
source 12 relative to the reflector 10. It can be also provided
that the reflector 10 is movable relative to the light source 12.
The light source 12 is held in a lamp support 20 which is supported
turnably about an at least approximately horizontally extending
axis 22 at least indirectly on the reflector 10. The turning axis
22 extends near the upper edge of the lamp support 20. The light
source 12 extends with its glass container, in which it forms
during operation a light arc 24, through the opening 19 in the
reflector 10, so that the light emitted by the light arc 24 is
reflected by the concavely curved reflection surface of the
reflection 10. A screening device 26 can be associated with the
light source 12 for screening a part of the light which is emitted
by the light source 12, so that it does not fall on the reflector
10. The screening device 26 can produce a bright-dark limit of the
light beam exiting the headlight.
[0012] An electrically adjusting device 28 engages the lamp support
20 eccentrically to the turning axis 22. The adjusting device 28
turns the lamp support 20 together with the light source arranged
on it around the axis 22. The adjusting device 28 has an electric
motor 30 operating as a drive, so as to rectilinearly displace the
adjusting rod 32 engaging the lamp support 20 for example through a
transmission. The electric motor 30 is formed for example as a
stepper motor. From an adjusted base position, it can provide
turning to each position of the adjusting rod 32 and thereby the
lamp support 20 by a predetermined number of steps of the electric
motor 30.
[0013] The lamp support 20 and the light source 12 held in it are
movable by the adjusting device 28 between an end position for low
beam and at least one further position. When the lamp support 20
with the light source 12 is located in the end position for low
beam, the light emitted by the light source 20 is reflected by the
reflector 10 as a low beam with an upper bright-dark limit, through
which the distance of the low beam is limited so that it does not
cause blinding of the countertraffic. When the lamp support 20 with
the light source 12 is located in the further position, the light
emitted by the light source 20, because of the changed arrangement
of the light source 20 relative to the reflector 10, is reflected
by the reflector 10 as a high beam with a greater distance than the
low beam and with lower clearly pronounced bright-dark limit.
[0014] In FIG. 1 the lamp support 20 and the light source 12 are
shown in solid lines in their position for low beam. The lamp
support 20 can be located in abutment against an abutment 34, with
which the exact arrangement of the light source 12 relative to the
reflector 10 is guaranteed, as required for producing the low beam
with the prescribed position of the bright-dark limit. The light
source 12 in the position of low beam is arranged relative to the
reflector 10 so that the light emitted by its light arc 24 is a
downwardly inclined light beam which has an asymmetrical upper
bright-dark limit.
[0015] FIG. 2 shows a measuring screen 80 arranged at a distance in
front of the headlight and illuminated by the light beam which
produces low beam by the headlight in the operational position. The
measuring screen 80 has a horizontal central plane HH and a
vertical central plane VV which intersect each other in a point HV.
The measuring screen 80 represents the projection of a roadway, by
which the light emitted by the headlight is illuminated. The
headlight is designed for right traffic, so that the traffic side
itself is the right side of the measuring screen 80 while the
countertraffic side is the left side of the measuring screen 80.
The low beam produced by the headlight illuminates the measuring
screen 80 in a region 82. The region 82 is limited from above by
the bright-dark limit, which at the countertraffic side or the left
side of the measuring screen 80 has a horizontal portion 83 and at
the traffic side or the right side of the measuring screen 80 has a
portion 84 which extends to the right starting from the horizontal
portion 83. The horizontal portion 83 of the bright-dark limit
extends approximately 1%, correspondingly approximately 0.57% under
the horizontal central plane HH of the measuring screen 80. The
portion 84 of the bright-dark limit is raised at an angle of
approximately 15.degree. to the horizontal central plane HH. The
distribution of the illumination intensities in the region 82 is
identified by several lines 85 which have the same illumination
intensities or so-called isolux lines.
[0016] FIG. 4 shows the lamp support 20 with the light source 12 in
an end position for high beam with broken lines. In its end
position for high beam, the lamp support 20 is turned relative to
the end position for low beam in clockwise direction around the
axis 22. The light arc 24 of the light source 12 in the end
position for high beam is turned relative to the end position for
low beam relative to the optical axis of the reflector downwardly
and toward an apex of the reflector 10. The lamp carrier 20 in the
end position for high beam can be also located in abutment against
an abutment 36. In addition, the screening device 26 can be removed
from the path of the beam of the light emitted by the light source
12 partially or particularly. With the changed arrangement of the
light source 12 relative to the reflector 10, the light emitted by
the light source 12 is reflected by the reflector 10 with another
characteristic than in the case of the arrangement of the light
source 12 in its end position for low beam.
[0017] FIG. 3 shows the measuring screen 8 which is illuminated by
a light beam produced by the headlight with a light source 12 in
its end position for high beam. The high beam illuminates a region
92, in which several isolux lines 95 are identified to illustrate
the illumination intensity distribution. The region 92 illuminated
by the high beam is offset upwardly relative to the region 82
illuminated by the low beam and has no or at least only less
clearly pronounced bright-dark limit. The extension of the region
92 in a horizontal direction is at least approximately equal to
that of the region 82. In the region 92 moreover a pronounced
maximum of the illumination intensity with higher illumination
intensity values than in the region 89 is provided. The high beam
generated by the headlight has a greater distance than the low beam
generated by the headlight.
[0018] It can be provided that the lamp support 20 with the light
source 12 is movable only between the end position for low beam and
the end position for high beam. Alternatively, it can be also
provided that the lamp support 20 with the light source 12 can
assume one or several intermediate positions between the end
position for low beam and for high beam. The characteristic of the
light beam produced by the headlight is approximately similar to
the characteristic of the high beam, the closer the lamp carrier 20
with the light source 12 is arranged relative to the end position
of the end position of the high beam. With the lamp carrier 20 with
the light source 12 is moved from its end position for low beam in
direction to the end position for high beam, the distance of the
light beam produced by the headlight increases and the bright-dark
limit is pronounced less clearly, so that the countertraffic can
not be blinded.
[0019] The headlight, in addition to the adjusting device 28 also
has a light width adjusting device 40 for changing the light width
of the light beam produced by the headlight. The light width
adjusting device 40 turns the headlight insert 14 about an axis 42
which extends at least approximately horizontally. The light width
adjusting device 40 can have an electric drive motor 44 for moving
an adjusting element 45 connected with the reflector 10, so as to
provide a turning of the headlight insert 14 about the axis 42. The
headlight in a not shown manner can be mounted on the body or on a
structure of the motor vehicle. During a change of the loading of
the motor vehicle or during the driving the inclination of the body
or the structure of the motor vehicle can change, whereby the
inclination of the headlight is changed also and thereby the light
width of the light bundle produced by it. In particular for the low
beam, its light width and thereby the position of its bright-dark
limit 83, 84 in a vertical direction is exactly prescribed to
prevent a blinding of the countertraffic. The light width adjusting
device 40 serves for maintaining of the light width of the light
beam produced by the headlight at least approximately constant,
regardless of the loading of the motor vehicle. For this purpose
the headlight insert 14 is turnable correspondingly around the axis
42. When the vehicle is unloaded, the light width and thereby the
position of the bright-dark limit 83, 84 is adjusted correctly.
When the motor vehicle is loaded, the headlight insert 14 is turned
by the light width adjusting device 40 around the axis 42
downwardly so that the light width and thereby the position of the
bright-dark limit 82, 84 are adjusted again correctly.
[0020] An electrical preswitching device 46 is provided for the
light source 12. It provides operation of the light source 12
independently from its operational condition with the required
electrical voltage, a current and a resulting electrical power. The
preswitching device 46 serves for igniting the light source 12 and
for providing a stabile operation of the light source 12.
[0021] In accordance with the present invention, a safety device 50
is provided in the headlight. The safety device 50 monitors,
whether the adjusting device 28 operates in an orderly fashion and
the lamp support 20 with the light source 12 is located in a
correct position for the corresponding operation position of the
headlight, or in other words low beam or high beam. With the safety
device 50, for example the operational current of the electric
motor 30 of the adjusting device 28 is monitored. When the
adjusting device 28 is activated the electric motor 30 is supplied
with current of a predetermined current intensity to move the lamp
support 20 with the light source 12. When the actual current
intensity deviates from the predetermined current intensity, a
faulty operation of the adjusting device 28 can occur and as a
result the lamp support 20 with the light source 12 is located not
in the position for the selected operational condition, in other
words low beam or high beam. In the case of an interruption of the
electrical connection of the adjusting device 20 with the required
voltage source 52, for example because of the cable breakage, no
operational current is available for the electric motor 30 which
can be recognized by the safety device 50 as an error. Also in this
case the lamp carrier 20 with the light source 12 is not located in
the position which is required for the corresponding operational
condition, or in other words low beam or high beam.
[0022] When the safety device 50 recognizes an error, it actuates
the operations, with which a blinding of the countertraffic is
avoided, or at least reduced. It can be provided that the safety
device 50 influences the preswitching device 36 of the light source
1 so that the light source 12 is operated by the preswitching
device 46 with electric power which is reduced relative to the
normal electric power. The electric power is reduced so much that
no or only a little blinding of the countertraffic is caused. The
electric power can be reduced to zero so that the light source 12
is no longer operated and shut off. Conventionally, two headlights
are provided on the vehicle, and with the use of a gas discharge
lamp as the light source 12 also when only one headlight is
operated, a sufficient illumination is guaranteed.
[0023] Alternative or additionally to the above explained reduction
of the electrical power, with which the light source 12 is
operated, it is possible to control by the safety device 50 the
light width adjusting device 40 in the case of error so that the
headlight insert 14 is turned by it around the axis 42 downwardly
and thereby the light width of the light beam produced by the
headlight is reduced. For the case when the lamp support 20 with
the light source 12 is located in the position for high beam at the
measuring screen 80 is illuminated in the region 92 in FIG. 3, the
light beam is lowered so that the region 92 is lowered downwardly
to the position 92' shown with broken lines in FIG. 3. The region
92' is lowered so much that it no longer extends over the
horizontal central plane HH of the measuring screen 80. By the
lowering of the light beam with the light width adjusting device 40
a blinding of the countertraffic is avoided or at least reduced. In
addition as described above, the vehicle power in which the light
source 12 is operated, can be reduced as well.
[0024] It can be also provided that with the safety device 50, the
relative arrangement between the light source 12 and the reflector
10 is monitored to the relative position, whether it corresponds to
a predetermined position. With the safety device 50 it is therefore
monitored whether the lamp support 20 with the light source 12 is
located in the position for the respective operational condition,
or in other words low beam or high beam. It can be provided that a
position sensor 52 is arranged correspondingly at the abutment 34,
36 which determines the position of the lamp support 20. The sensor
detects the abutment of the lamp support 20 against the
corresponding abutment 34, 36. A potentiometer, an end switch or a
position-indicating sensor can be used as the position sensor 52.
When the lamp support 20 is located not in the position at the
correct abutment for the corresponding operational condition of the
headlight, or in other words the operational position for low beam
in the abutment against the abutment 34 or in the operational
position for high beam in the abutment against the abutment 36,
this is recognized by the safety device 50. As in the previous
embodiment, it reduces the power of the light source 12 or turns it
off and/or turns downwardly by the light width adjusting device 40
of the headlight insert 14.
[0025] Alternatively or additional to the above described
embodiment, a reduction of the distance of the light beam produced
by the headlight insert 14 in the case of error can be performed so
that, with the safety device 50 a screening device 54 is activated.
It screens a part of the light beam with the greatest distance
produced by the headlight insert 14 at least partially. The
screening device 54 can be formed as a movable screen or stationary
and formed with changeable light permeability.
[0026] It will be understood that each of the elements described
above, or two or more together, may also find a useful application
in other types of constructions differing from the types described
above.
[0027] While the invention has been illustrated and described as
embodied in headlight for vehicle for producing a low beam and at
least one light beam for a greater range, it is not intended to be
limited to the details shown, since various modifications and
structural changes may be made without departing in any way from
the spirit of the present invention.
[0028] Without further analysis, the foregoing will so fully reveal
the gist of the present invention that others can, by applying
current knowledge, readily adapt it for various applications
without omitting features that, from the standpoint of prior art,
fairly constitute essential characteristics of the generic or
specific aspects of this invention.
* * * * *